Study on sodium extraction and transport at Monju

Isobe, Yuta; Tanigaki, Takanori; Tone, Kohei; Joboji, Yuya; Matsui, Kazuaki; Obata, Ikuhito

Proceedings of 31st International Conference on Nuclear Engineering (ICONE31) (Internet), 8 Pages, 2024/11

The prototype fast breeder reactor Monju is a loop-type, sodium-cooled nuclear reactor in Japan. Monju transitioned; to decommissioning in 2018, and the first phase of decommissioning was completed in FY2022 by unloading all the fuel assemblies from the reactor core and Ex-vessel storage tank (EVST) to spent fuel pool. In FY2023, Monju has moved to the second phase of decommissioning, and currently we are working to unload neutron shields and other core elements from the reactor core and EVST to spent fuel pool, and to dismantle water and steam system such as turbine generator, condensers, feed water heaters, etc. Monju has a primary sodium system that cools the reactor core and fuel, and a secondary sodium system that transfers heat. Sodium in the primary system is radioactive, but sodium in the secondary system is non-radioactive. We plan to extract non-radioactive sodium first, so we are first considering this in advance. At present, we have decided on the sodium extraction area where the ISO tank for extraction of non-radioactive sodium will be installed. In addition, we also considered the route for transferring sodium from the existing tanks to the ISO tanks. New piping for these operations will be added, and the sodium will be extracted using existing gas systems and electromagnetic pumps. We will take appropriate measures to sodium leakage and continue to consider safe and rational extraction and transportation methods.

Cs-Te corrosion depth dependence on distribution of chromium carbide precipitation in high chromium steel

Sasaki, Koei; Fujimura, Ryota*; Tanigaki, Takanori; Matsubara, Masanori*; Fukumoto, Kenichi*; Uno, Masayoshi*

Journal of Nuclear Science and Technology, 54(2), p.139 - 146, 2017/02

AA2016-0211.pdf:2.83MB

https://doi.org/10.1080/00223131.2016.1214628

In an attempt to investigate Cs-Te corrosion depth dependence on distribution of chromium carbide precipitation in high chromium steel, Cs-Te corrosion out-pile tests of two 9Cr steels with different distributions of chromium carbide were carried out at 975K for 100h and their corrosion depths were compared. The corrosion is obviously more advanced in a specimen which has grain boundary carbide than in the one that does not. A considerable reason of the result is that the carbide distributed at grain boundaries promoted the corrosion reaction and the corrosion extended along the grain boundary. This is the first case in which the Cs-Te corrosion depth dependence on distribution of chromium carbide precipitation in Fe-Cr steel is clarified experimentally.

Development of nuclear security technologies for a large public event, 1; Project overview

Koizumi, Mitsuo; Takahashi, Tone; Mochimaru, Takanori*; Yamaguchi, Ikuto*; Yoshimi, Yuki*; Yamanishi, Hirokuni*; Wakabayashi, Genichiro*; Tanigaki, Minoru*; Harada, Hiroshi*; Masaki, Hiroko*; et al.

no journal, , 

no abstracts in English

Development of nuclear security technologies for a large public event, 3; Neutron source detection

Mochimaru, Takanori*; Koizumi, Mitsuo; Takahashi, Tone; Yamaguchi, Ikuto*; Yoshimi, Yuki*; Yamanishi, Hirokuni*; Wakabayashi, Genichiro*; Tanigaki, Minoru*; Harada, Hiroshi*; Masaki, Hiroko*; et al.

no journal, , 

no abstracts in English

Development of nuclear security technologies for major public events

Takahashi, Tone; Koizumi, Mitsuo; Mochimaru, Takanori*; Yamaguchi, Ikuto*; Yoshimi, Yuki*; Tanigaki, Minoru*; Goto, Jun*; Harada, Hiroshi*; Masaki, Hiroko*; Ito, Fumiaki*

no journal, , 

no abstracts in English